Method and machine for planing helical teeth, more particularly for bevel gears



July 3, 1923.

H. BRANDENBERGER METHOD AND MACHINE FOR PLANING HELICAL TEETH, MOREPARTICULARLY FOR BEVEL GEARS Filed Jan. 5, 1921 3 Sheets-Sheet l July 3,1923. 1.4 0.640

H. BRANDENBERGER METHOD ANDMACHINE FOR PLANING HELICAL TEETH, MOREPARTICULARLY FOR BEVEL GEARS Filed Jan. 5, 1921 3 Sheets-Sheet 5 ./43 5545 I 52 8L'O 5 Patented July 3, 1923.

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METHOD AND MACHINEF RflANINdHELIdAL TEETH,

- v BEVELHIGEARS.

MORE'J'PABTICULIARLY non 1 Application filed January 5, 1921. serial-N6, 435,268.

' To all whom it'may concern:

Be it known thatI, HEINRIGH'BRANDEN BERGER, a subject of theRepublicofSwit zerland, residing at Degengasse, V1enna 5 XVI, Austria, haveinvented certam ne'w and useful Improvements in Methods and' movestoandflfro in a straight line, during" which, as when planingstraightfteeth, the" line of motion of the point of the cutting edge ofthe tool passes through the apex of theicone. The rectilinear movementof the 0 toolican be derived 'from' a crankdrive and is the same for twointermeshing gear wheels,.

,the directionof'rota tion of the bevel blank being however reversedwhen cutting the -mating gearwheel. The resulting path 01" the out isthereby a "relative motion of the" cutting tool to the bevel-blank. Suchheli cal teeth have hitherto been cut in a manner whereby the rotarymovement of the work has been utilized as 'a d ividing motion, thecutting tool at each succeedingcut being allowed to cutthe nexttooth,'whereby'heli-' "cal' teeth with a Very small spiral angle (skew) wereobtained. In order to obtain teeth with larger spiral angles 'by-thismethod,'the"-*work (bevel blank) had'to 'be 1 ro-' tated further duringthe .cut and rotated back again duringthe return of'the=j"cutting.-'

' tool'the aniount'oi': the excess rotation.

I According to this inventionthls reverse mimbe bf pitch intervalswhereby itis advisable. to omit asm'any teeth as possible, 1n

order to obtain a largeinclination 'o-f fthe helical teeth. The rotationof the work' is 48-h'er'eby a continuous one; capable of being aunlformoran irregular-movement recurring away stroke in accord'ance with thesame' lawp I "One fe'atureof the"iniiention consistsi in '60- the methodof planing helical' teeth, -mo re particularly *for 'beielfgeaiijwheels," wh'erein the; ratio '5 of the number of strokes of theeuttirig' tool to the number 01f reifoluti'o'nsbf the work "is so"proportioned, that the cutl tingtool misses one or more pitch intervalsthe tool to-the bevelblanl'z. Theline o f the relative movementencloses'with the line of motion of the tool an angle varyirig accord Yi In workshop practi e, helical: teeth-can .rotationi's avoided; in-thatthe tool misses a whereby it it possible it form rental teeth with thegreatest practicable inclination 7 I 1 The helical -shape ofthe eethresults in I I I consequence of thekjrelativemovement, org;

ing, to the circumstances, theso called-fspiral angle, which'is'dependent upon'i'the number of pitch intervals which arefmissed antetime/H I 7 The'inventiofiiflates furtherit O a i V. "duneplani-nslheliwl teeth ion'ibevei,...i wheels Whmh or different sii ralanglestool heads va e in toorsl'ide io 'guides are, 'WiiththetOOlSQfcapable of adjustment about "an axis" perpendicular" tog,"

their lines of 'motion'in'th'e circle'or circular arc; in such a manner,th'atthe directioiibf f.

the tool positionlca'n bealter d wh i l point of the ciittlng edgeo'fthe t001: :W n

always'remaininthesame'plaCQ- I A constructional lf rmof the inVentio-Qis illustrated" in the 'accomp'anying."drawi'ngl"1 Fig. 1 shows thestroke "conditionsbf;a

tingitool at the pitch cone, in thej"lower part of the figureinaccordance with the known method and in the upper part in accord-i ancewiththe jme-thod ofthe'present' ini en tionyand if" 1 Fig. 3 isa"d'iagram'. "Figs. 4 to 6 illustratetheimost essential part of themachine; the} tool-j'slide'gui'de with the 'to tool head arrangedfontwo-tools'. i i Fig. 4 isa plan-view;

6 a side elevation, 3 from' the-position shown in "Fig-4a, and; fIrFig'bS is a :detaiL I j isutherefore the approach and 1 3 the "run outof the cutting toolQ In Fig; Qi'ftheflsrir- 1 face er the bevel 'wheelhas fbeen developed into a'plane?" Thetool holder is'driireir; 'byfmeans of a crank, for exampl eifandlthje mo-v tion of the "bevel,blank,- as ialsojthat' of the.

icrankpinfis: unifo m: The spiral '5",,=j6,7;

8 (in the lower part 'ofFig. ey'repre'sents the *relative movementof'thecuttiilg 123019110 j H I'uRIcH BRANDENBERGERQOF:VIENNA, AUSTRIA,

Fig. 2the s'pir-alsgenerated'by" the"cut I N Fig. '5 a section takenalong I II"'in Fig.1 7 4 c. and

Fig: shows the 'tool heads displaced 1 "i v 1] to the surface of thework during the cutting stroke, the spiral 8, 9,10, 11, that during thereturn. After the tool has returned to its starting point, the work(bevel blank) has rotated the amount of one pitch interval, so that thesucceeding tooth will be cut. The advance, that is the distance by whichthe beginning and end of the helical tooth are offset to one another,amounts to 1/5 of a pitch interval, the mean spiral angle to 2. I I

As shown in the upper part of Fig. 2, the

bevel wheel set out in the lower part of the bevel blank. the return ofthe ram takes -twocute is seven times as great as in the place with thecutting, tool swivelled back.

The advancelof the cutting tool between lower part of Fig. 2, becausethe bevel blank has moved forward seven times faster under the cuttingtool during the out, there- 'fore 7/5 of the pitch. interval: the meanspiral angle amounts to about 14. It the rotation of the bevel blankbetween two cuts be continued by anumber of pitch intervals which isneither contained in the total num ber of the teeth of the blank to becut nor has a common measure therewith, then after several revolutionsof the bevel wheel all the teeth will be cut ,wvithout any supplementarydividing, therefore without the ne cessity of a dividing mechanism. Onthe contrary, an automatic dividing without dividing mechanism takesplace. i f

In Fig. 3, the straight lines .1. to 25" represent theteeth of thebevelwheel, while the points situated below show the teeth which are cut ateach of the revolutions I, II-VI1 .of the bevel wheel. As the bevelwheel rotutes forward seven pitch intervals at each double stroke of thecutting tool, then it will have to nfiakeseven revolutions beforegreater angularity can'be obtained. t-

all the teeth are" cut. By the missing ot. teeth being carried further,teeth with It is possible, for instance to rotate the work .(.bevelblank) so quickly, that the cutting i tool w1ll cut into just cut.

the tooth preceding that In order that the back of the prismatic stoolwill lie within the tooth space, it will'be necessary to adjust the-toolto the direction of this relative movement, the line of mo tion of thepoint of the cutting'edge of the tool however, passing through the apexof the cone, as when planing straight teeth,

1y, co-adjacent centers.

swivelled along these circular guides are..

The apex of the cone of thework is fixed in the machine as to the pointof intersection of the pivot, about which the movementsfor generatingthe toothshape takes place. The adjustment of the point of the cuttingedge of the tool is thereby also fixed. H j l The invention alsocomprises a machine for planing bevel gear wheels with helical teethwhich will meet these two require ments in a simple manner by means ofthe design of the tool head; firstly, adjustment of the tool to anydesired angle, and secondly, adjustment of the point of the cutting.edge of the tool to the specific constant position. The firstrequirement, adjustment of the tool to the spiral angle existing at anyparticular instant is-met by the tool holder being rotatably mounted inthe tool head. In order to satisfy the second requirement,

fixed position of the point of the cutting, edge. of the tool at allspiral angles, the

axis of this rotation is so disposcd that it passes through the pointwhich the point ot the cutting edge of the tool occupies. The positionof the tool in the tool holder. will hereby be fixed by means of a gaugediningv the settin up of the tool. By this arrangement of the tool head,it is possible by means of a single adjustment, that is by ro-tatinr thetool holder, to bring the tool into the.

correct position for another spiral angle, be cause the'point ofthecutting edge of the tool does not depart during the rotation of the toolholder, from the position to which it has been once correctly adjusted,as it is situated on the, axis of this rotation.

the axes of rotation vwhich can be made to pass through the point of thecutting edge of the tool, it is preferable to adopt that which isperpendicular to the tangential,

for each tool, which for instance in a rolling-' off machine will,be'swivelled by means of toothed segments, while they, are coupled toone another by means of a right and left handed screw 23, so that theycan be'swiv elled for cutting teeth of different thicknesses, but remainin the once adjusted position during the operation of the machine. Each,slide guide contains a slide 24, 25. respectively, each of which isprovided with a .011 cular guide 26, 27 respectively, having close-Capable of being jaws 28, 29 upon which the;carriers 30, 31 tor thetools 32, 33, are mounted, capable of swinging about-34, 35respectively. The

tools are inserted in the tool head from the front by their guideprojectionsv36 (Fig. 6).

and locked by means of set screws 37 and the plate 38 adapted to besecured in front. According to the apparatus so far described, the toolscan be so adjusted about imaginary axes 39, 40 perpendicular to thedirection of their motion in the slide guides 21, 22, namely in the arcsabout the centers of the circular guides 26 27 that the forward cuttingedge of the tool always remains stationary, even if the direction of thetool to the line of motion of the'tool head (towards the apex of thebevel blank) be altered; that is. to say, the axis of the tool and theline of motion of the tool enclose any angle whatever, as shown forexample in Fig. 7

In order to lift the tool away from the work at the return, arms 41, 42(Fig. 5) branch off from the tool heads 30 31' capable of swinging about34, 35, the said arms being connected, by means of closely juxtaposedvertical pins-43, 44 to the side plates 46,747 leading to a roller 45.The roller is which the roller travels.

actuated by a lifting device which for example is constituted by a rail48 moved regularly backward and forward, upon In this apparatus thepivot pins 43,44 as well as the extreme forward edge of the tools, lieexactly or approximately central to the circular guides'26, 27, so thatin consequence, the tools 32, 33 or the tool heads 30 31 can bedisplaced in the arcs without there-- by requiring the lifting device toalter its position. During the working stroke of the tools 32, 33directed towards the cone apex of the bevelkblank, the rail 48 is swungout forwardly and springs 49, 50 thereby pull the tool heads 30, 31 intothe working position; on the return of the tools the rail 48 movesrearwardly; whereby the tool heads consisting in proportioning the ratioof the a number of strokes of the. cutting tool to the number ofrevolutionsof the constantly rotating work so that the cutting toolmisses a number of pitch intervals.

2. The method of planing helical teeth as claimed in claim 1 wherein thecontinuously rotating work is rotated forward between two cuts a numberof pitch intervals which is not contained in the total number of teethto be formed on the work and does not I a have a common measuretherewith.

In a planing machine for making bevel gear wheels with helical teeth,tool'slide guides, tools and tool receiving heads ad-" justable in acircular are about an'axis perpendicular to their line of motion-in sucha mannerthat the direction of the tools to the line of motion of thetool heads maybe altered without changingthe cutting edges of the toolsfrom their positions substantially centrally of the arc. v V

4. In a planing machine as claimed in claim 3, mechanism forraisingthe-tools on their return stroke, including a lifting rail,

a roller associated therewithand positioned substantially at the centerof the displacement of the arc of thetools,'and pins suspended from theroller for operable engagement with the tools, substantially as and, forthe purpose set forth.

In testimony whereof I have signed my name to this specification. I

Ing. HEINRICH BRANDE BERcEi'i.

